Staining Yeast

INTRODUCTION

Staining yeast cells for the presence and localization of antigens has been particularly challenging because of several factors. The yeast cells are small, making the resolution of any antigen difficult; they have a thick cell wall that antibodies cannot penetrate and that is difficult to remove; and they grow in suspension, making handling difficult. Background problems can be especially severe, particularly with polyclonal antibodies, because many antisera contain antibodies to yeast cell-wall components. The difficulties encountered in localizing antigens in yeast can be overcome by using fluorochrome-labeled secondary antibodies, controlled enzymatic removal of the cell wall, and by binding the cells to a solid phase (e.g., poly-L-lysine-coated slides).